# File lib/facet/lisp-format.rb, line 1556
        def connect(directives)
          @clauses = []
          clause = []
          directives.each do |d|
            if d.is_a? ClauseSeparator
              @clauses << clause
              clause = []
              if d.colon_mod?
                if @default == -1
                  @default = @clauses.size
                else
                  raise SyntaxError.new(d.pos),
                    'default clause has already been set'
                end
              end
            elsif d.is_a? EndConditional
              @clauses << clause
              break
            else
              clause << d
            end
          end
          must = 'two' if colon_mod? and @clauses.size != 2
          must = 'one' if at_mod? and @clauses.size != 1
          unless must.nil?
            raise SyntaxError.new(@pos), "must specify exactly #{must} clauses"
          end
        end